The invention relates to an adhesive binder with a machine frame and a plurality of processing stations attached to the machine frame, with at least two transport clamps for transporting book blocks, at least one closed guide track for the clamps, and at least one device for changing the overhang of the book blocks.
Adhesive binders are used for the production of adhesive-bound or perfect-bound books (softcover) or book blocks for books with hard covers (hardcover), wherein signatures and/or individual sheets, gathered to form a book block, are joined by applying a general adhesive or glue onto the previously processed book block back and are subsequently provided with a cover (softcover) or with a lining strip (hardcover). The overhang is the part of the book block projecting from a transport clamp of the adhesive binder in the direction of the respective processing stations and on which the various processing steps are carried out in the adhesive binder. The amount of the overhang may have to be changed in dependence on these processing steps, for example when attaching an envelope or a lining strip to the book block. The possible binding methods and the product variants generally depend on the machine components of the adhesive binder. The latter essentially consists of the following functional units: block transporting system, block insertion station, back processing station (back milling), back adhesive application station, intermediate drying station, side adhesive application station, back-reinforcement station, stations for fitting on of an envelope and/or lining strip, pressing on an envelope and/or lining strip, delivery station, and drying station.
According to the prior art, roller chains with movably interlocking individual links are preferably used as conveying means in adhesive binders. The chains function to move the transport clamps forward. The transport clamps are guided by a guide track that is connected to the machine frame of the adhesive binder. Each transport clamp is provided for this with several rolls which roll off the guide surface of the guide track.
In addition to adhesive binders provided with a collating machine and thus automatic feeding, small adhesive binders with start-stop operation are also known, which are frequently equipped with a manual feed station. For this, the book blocks are inserted individually and manually by the machine operator into a stopped transport clamp. The transport clamp then moves the book block past various processing stations through the adhesive binder.
An adhesive binder with automatic feed-in is described, for example, in the EP 2738011 A2. This adhesive binder comprises several processing stations, for example a block inserting station, a back-processing station (back milling device), an adhesive application station, an adhesive application control unit, an envelope feeder and/or a lining station, an envelope and/or liner pressing station, a delivery station and a drying station. This adhesive binder is furthermore provided with at least two book block transport clamps, as well as at least one closed guide track on which the transport clamps circulate and pass the processing stations.
The option of producing individual copies of books or small numbers thereof is increasingly desired not only in the softcover range, but also for producing lined book blocks in the hardcover range. Producing these book blocks for hardcover books requires an adhesive binder provided with a lining station. When attaching the lining strips, it should be possible to adjust in dependence on the end product the excess lining material over a specific region of the book block back. On the one hand, a lining strip with the correct dimensions must be made available by the lining station while, on the other hand, the overhang of the book blocks for binding must exceed the desired excess length of the lining material.
According to page 307 of the technical manual “INDUSTRIELLE BUCH BINDEREI” [Industrial Bookbinding] by Liebau/Heinze, 2001 (ISBN 3-88013, 596-7), the overhang can be selected within specific ranges. In other words, a device for adapting the overhang to the technical requirements of small adhesive binders is basically known. Since the transport clamps of presently known adhesive binders are arranged so as to be fixedly attached to the frame, meaning they are connected immovably to the machine frame or a support structure during the adhesive binding operation, the position of a processing station embodied as resting/vibrating table must first be adjusted, relative to the transport clamps, for a change in the overhang. All other processing stations, such as the back milling, adhesive application, envelope-attachment or lining stations, the pressing and delivery stations, must also be adapted to this change, either manually or automated with the aid of a motor in the case of modern systems.
However, to realize the change in the book block overhang and to maintain the required position accuracy of approximately 0.1 mm requires a considerable expenditure in mechanical equipment, such as linear guides for actuators, adjusting axes with servomotors, as well as sensing equipment in the processing stations. Added to this are relatively complicated sequences in the software.
If we were to follow along the path of solutions known so far, this could result in particular in the development of a height-adjustable back milling device with massive and expensive linear guides. The types of adhesive units, such as the hotmelt roller adhesive application unit, the PUR (polyurethane) adhesive application unit, and the side adhesive application unit would have to be embodied height-adjustable, which could result in complicated structural solutions, especially for an option with “mobile, replaceable adhesive units.”
A further problem, specifically in the range of small adhesive binders, are the costs associated therewith, regardless of the existence of a lining station and thus the option of producing book blocks for hardcover books.